In the disclosure of the present invention reference is mostly made to drug delivery devices used e.g. in the treatment of diabetes by delivery of insulin, however, this is only an exemplary use of the present invention.
Drug injection devices have greatly improved the lives of patients who must self-administer drugs and biological agents. Drug injection devices may take many forms, including simple disposable devices that are little more than an ampoule with an injection means or they may be durable devices adapted to be used with pre-filled cartridges. Regardless of their form and type, they have proven to be great aids in assisting patients to self-administer injectable drugs and biological agents. They also greatly assist care givers in administering injectable medicines to those incapable of performing self-injections.
Performing the necessary insulin injection at the right time and in the right size is essential for managing diabetes, i.e. compliance with the specified insulin regimen is important. In order to make it possible for medical personnel to determine the effectiveness of a prescribed dosage pattern, diabetes patients are encouraged to keep a log of the size and time of each injection. However, such logs are normally kept in handwritten notebooks, from which the logged information may not be easily uploaded to a computer for data processing. Furthermore, as only events, which are noted by the patient, are logged, the note book system requires that the patient remembers to log each injection, if the logged information is to have any value in the treatment of the patient's disease. A missing or erroneous record in the log results in a misleading picture of the injection history and thus a misleading basis for the medical personnel's decision making with respect to future medication. Accordingly, it may be desirable to automate the logging of ejection information from medication delivery systems based on the assumption that ejected doses corresponds to injected doses.
Addressing this need injection devices integrating a monitoring/acquisition mechanism into the device itself have been proposed, e.g. as disclosed in US 2009/0318865 and WO 2010/052275. Alternatively, the desired functionality may be provided by an electronic “add-on”module adapted to be attached to and measure signals generated by a standard mechanical pen device, e.g. as disclosed in WO 2007/107564 and EP2014/074475.
To keep costs down and to make such devices simple to use it may be desirable to provide devices which do not need to be recharged. Correspondingly, such devices are normally equipped with either a replaceable battery or a power source with a capacity to last the expected lifetime of the device.
Some devices may however have a significant storage time from production to first use and furthermore a very limited time of actual use compared to in-between use time. Therefore such devices often have their power source disconnected from the electronics while stored and go into sleep-mode between uses. Since all power sources to some extend discharge over time and needs to power at least part of the electronics between uses in order to be able to “wake-up” from sleep-mode, it is often necessary to equip a device with a power source of more than ten times the actual required capacity, because more than 90% of the power is used during storage and in between uses.
Having regard to the above, it is an object of the present invention to provide an assembly with a power source which for a given size/capacity of the power source has improved storage time as well as improved use time. The assembly may be in the form of a portable electronic device. The device should be user-friendly and adapted for cost-effective manufacturing.